Apparatus for mixing concrete



Jan. 14, 1964 p, MaOKINNEY 3,117,640

APPARATUS FOR MIXING CONCRETE Filed July 27, 1959 INV ENTOR. Paul M Mac Kuzmgz l,

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United States Patent Ofiiice 3,117,640 Patented Jan. 14, 1964 3,117,640 APPARATUS FOR MIXING CONCRETE Paul M. MaeKinney, 1012 E. Geneva Road, Wheaton, Ill. Filed July 27, 1959, Ser. No. 829,852 9 Claims. (Cl. 177-80) This invention relates to apparatus used in the mixing of concrete and specifically to apparatus utilized in the measuring and dispensing of the aggregate materials and water which are components of the concrete.

One of the problems encountered in the mixing of concrete is the entrained moisture in the aggregate materials. This moisture if not properly accounted for in the mixing of the ingredients of which the concrete is composed will result in the concrete having a poor consistency or a low slump. Numerous devices have been devised in the past in order to properly measure and account for the entrained moisture in the aggregate materials. However, most of these devices are unable to accurately compensate for the entrained moisture when the mixture of moisture and aggregate materials is heterogeneous. The lack of homogeneousness is particularly true in aggregate material having a high percentage of entrained moisture. In such instances the moisture will tend to settle or drain to the bottom of the hopper or bin in which the aggregate material has been placed. If the variation in moisture is not properly accounted for, then, of course, any at tempt to compensate for the amount of moisture in the sand will be futile.

In a few instances attempts have been made to compensate for the variation in moisture. However, the devices proposed in these instances did not utilize such information so that the weighing or dispensing devices automatically receive such information or the results of such information and thus make the necessary compensations for the moisture. In most of the latter type devices it was necessary for the operator to interpolate the information and then manually manipulate the controls regulating the aggregate materials and the water to achieve the desired results.

For the above reasons, among others, I have invented a device having the foremost feature and object of automatically measuring and compensating for the moisture in the aggregate materials, regardless of whether the mixture of aggregate and moisture is heterogeneous or homogeneous, to provide concrete of a desired consistency.

A further feature and object of the invention resides in the provision of a measuring device that automatically increases the weight of aggregate and entrained water mixture an amount sufficient to provide the desired dry weight of aggregate.

A still further feature and object of the invention resides in the provision of a dispensing device that automatically decreases the amount of water added to the cement and aggregate by an amount substantially equal to the entrained moisture in the aggregate.

A still further object of the invention resides in the provision of a system that may be utilized with various types of water dispensing systems such as weighing devices, metering devices, and the like.

A still further object of the invention resides in the provision of a system and device as described previously which may be constructed of well known and commercially available components and is economical in cost.

These and other features and objects of the invention will be apparent upon reading of the specification with reference to the following drawings:

The drawing is a schematic illustration of the system embodying the invention.

In the drawing there is shown an apparatus for weighing the aggregate material generally denoted by the numeral 10 and apparatus for weighing and dispensing of the water generally denoted by the numeral 20. It should be kept in mind that while the apparatus shown both for the measuring of the aggregate material and the water accomplish this end by weighing, it will be apparent that other types of measuring devices may be used. Specifically, as will be explained in greater detail later on, the water may be measured by means of a metering valve or other volume measuring apparatus, rather than the scale as shown in the drawings.

The aggregate measuring apparatus includes the hoppers 22 and 24. One of the hoppers 22 is adapted to dispense sand or finer aggregate material and the second 24 is adapted to dispense the coarser aggregate material such as gravel. In this particular instance the hoppers 22 and 24 are of the bottom opening type having the chutes 26 in which the flow is controlled by the pivotally mounted doors 28. In the preferred form the hoppers 22 and 24 are constructed to discharge the aggregate materials at a substantially constant rate for reasons that will be clearly apparent later on.

Positioned immediately below each of the chutes 26 are a pair of spaced electrodes 30. The electrodes $0 are connected to a suitable source of electrical energy such as a generator by means of lead wires and conventional circuitry 32. As shown in the drawing, the electrodes 30 are spaced so as to be in the path of discharge from each of the hoppers 22 and 24. Thus, as the aggregate material falls from the hopper, a part of it will substantially fill the gap between the two electrodes spaced immediately below. In this manner the moisture in the aggregate material will provide an electrical conducting medium bet-ween the pair of electrodes.

The amount of electrical energy flowing in the circuit 34 to which the electrodes 30 are connected will be de pendent upon the amount of entrained moisture in the aggregate material. In other words, the greater the percentage of entrained moisture, the greater will be the electrical energy flowing in the circuit. Thus, as a result of this relationship, the amount of moisture can be calculated as long as the rate of flow of aggregate material is constant.

The aggregate material from the hoppers 22 and 24 is received in the bin or batcher 36 which is adapted to discharge into a conventional mixer 38 through the opening 40. The cement used in the concrete may be charged into the mixer 38 by any suitable means (not shown).

The bin 36 is provided with weighing apparatus generally denoted by the numeral 44. The weighing apparatus in this instance is of the beam balance type which includes the arms 46 mounted on the fulcrum members 47 and having the slidable weight members 48 mounted thereon. The ends of the arms 46 are secured together by means of the vertical member 50 which is secured at its upper end to the indicating device 52. The weights 48 are adapted to be set so as to provide a predetermined weight or measure of the aggregate material in the bin 36. When the bin contains the predetermined weight of aggregate material, the indicator 53 returns to its balanced condition.

'Each pair of electrodes 39 is connected by means of suitable electrical circuitry to the recording device 56 as shown in the drawing. The recording device 56 may be of any suitable type such as those which translate an electrical signal into a pneumatic signal of a proportional magnitude. The recording device 56 in turn is connected by means of the conduit 58 to the pneumatically operated valve 60. The valve 60 is of any suitable type adapted to proportional control so that the degree ofresponse is a function of the pneumatic signal received from the recorder 56. The valve 66 is positioned within the conduit 62 which at one end communicates with a source of fluid such as water as shown in the drawing.

The fluid in this instance is located in an elevated position so as to provide a positive head at the valve 60. As diagrammatically illustrated in the tank 65, the level of the fluid is maintained substantially constant by means of a float operated valve 68. Thus, upon opening of the valve 6%, fluid will flow therethrough at a predetermined rate commensurate with the degree of opening. The valve 60 is connected at its outlet side by means of the conduit 64 to a container 70 which is suspended from the vertical member 50 on the beam balance 44.

Prior to reaching the container 70, the fluid pouring through the conduit 64 passes through a divider valve 72 which divides the fluid into two portions, as will be explained more fully hereinafter.

The fluid that is received in the container 70 increases the weight on the right hand side of the fulcrum members 47 as can be seen from the drawings. The additional weight caused by the liquid will necessitate a larger amount of aggregate material to place the weighing apparatus in balance. Since the valve 69 is opened an amount dependent upon the percentage of entrained moisture, the amount of fluid is likewise correlated to the entrained moisture. Thus it is possible to correlate the amount of liquid dispensed into the container 70 with the entrained moisture so that the total Weight in the bin 36 is increased sufliciently to provide the required amount of aggregate material on a dry basis.

For example, if a load of 6,000 pounds of dry aggregate material is required, and the aggregate material has entrained moisture, the compensating apparatus will increase the total weight required to place the weighing apparatus in balance to approximately 6,316 pounds. Of this total weight, 316 pounds would be attributable to the entrained moisture with the remaining 6,000 pounds being atrributable to the aggregate material.

The water batcher as mentioned previously is adapted to dispense a predetermined selected amount of water to be used in the mixing of the concrete. The batcher 20 is connected to a suitable source of water (not shown) by means of the conduit 80. The conduit 80 may be provided with suitable valving, automatic or manual, to provide means for controlling the flow of liquid into the batcher 20. The batcher 20 in this instance is shown as including a beam type balance generally denoted by the numeral 82 for measuring the desired amount of water. The balance 82 includes the two pivoted arms 84 mounted on fulcrums 85 and having the weight members 36 slidably disposed thereon. At the right hand end the arms 84 are connected to the vertical member 88 which in turn is suspended from the indicating device 90. When the dial 92 is in its neutral position, the predetermined weight of water has been dispensed into the batcher 20.

A container 94 similar to container 70 is suspended from the left hand ends of the arms 84. The container 94 is adapted to receive liquid from the conduit 64- and the divider valve 72 as can be seen from the drawings. It should be pointed out that the liquid flowing into the valve 72 may be divided into any ratio of parts such as into equal parts or 2/3 to 1/3 or whatever is necessary to provide the desired ratio.

Since the container 94 is suspended from the left hand ends of the arms 84, the weight of the liquid therein will decrease the amount of water necessary to place the beams in balance. Thus as a result of the proportional response to the amount of entrained moisture in the sand, it is possible to diminish the amount of weight necessary to place the water batcher in balance an amount substantially equal to that entrained in the aggregate material.

In the example given previously, the liquid in the container 94 would diminish the water requirement by approximately 316 pounds. As soon as the predetermined amount of water is accumulated, it may then be discharged into the mixer 38 through the conduit 96. The discharge of the water batcher 29 is controlled by means of the manual valve 98 which is of conventional construction.

The containers and 94 in their preferred form are provided with means for discharging the liquid received during the weighing of each batch of aggregate material and water. The liquid may be discharged to drain or it stay in turn be recirculated by suitable conduits and the like to the source 66.

As was mentioned previously, the subject system may also be used in conjunction with other types of water measuring devices. In particular, the system may be used in conjunction with metering devices which measure the volume of liquid, rather than its weight. For example, the liquid which is received from the valve 69 could be utilized to preset or advance the metering valve or to divert an amount of the metered water so as to diminish the total amount of fluid that would be permitted to reach the mixer 38.

It should be pointed out that the invention disclosed herein may be used in conjunction with the slump weights that are commonly used in the concrete industry. Slump weights are merely weights that may be placed on the balance arms to increase or decrease the amount of water dispensed into the mixer to vary the slump of the wet concrete.

It is now apparent that the subject invention provides a system for automatically compensating for the moisture entrained in the aggregate materials. Thus it is possible to accurately arrive at a concrete having a desired consistency or slump without the necessity of trial and error methods.

Although a preferred embodiment of the specification has been described hereinbefore, it is to be understood that this is merely by way of example and in no manner is to be construed as a limitation. It is contemplated that certain modifications may be made within the scope of the claims without departing from the scope of the invention.

What is claimed is:

1. A weighing device including a moisture compensating system comprising hopper means for discharging at a substantially constant rate an aggregate material normally having some entrained moisture therein, measuring means for receiving and measuring the discharge of aggregate material, electrode means adapted to be connected to a source of electrical energy by suitable electrical circuitry, said electrode means mounted intermediate said discharge means and said measuring means and mounted in the normal path of discharge from said hopper means, whereby said entrained moisture actuates said electrode means so that electrical energy commensurate with the percentage of entrained moisture flows in said circuit, a valve means adapted to be connected to a source of liquid and, connected to said circuit for proportional actuation thereby, for controlling the flow of said liquid, and means for receiving said liquid, connected to said measuring means, whereby the liquid received in said means for receiving compensates for the entrained moisture in said discharge.

2. A weighing device including a moisture compensating system comprising hopper means for discharging at a substantially constant rate an aggregate material normally having some entrained moisture therein, measuring means for receiving and weighing the discharge cf aggregate material, spaced electrode means adapted to be connected to a source of electrical energy by suitable electrical circuitry, said spaced electrode means mounted intermediate said discharge means and said measuring means and mounted in the normal path of discharge from said hopper means, whereby said entrained moisture electrically connects said spaced electrode means so that electrical energy commensurate with the percentage of entrained moisture flows in said circuit, a valve means adapted to be connected to a source of liquid and connected to said circuitry for proportional actuation thereby so as to regulate the rate of flow of liquid, and means for receiving said liquid, connected to said measuring means, whereby the liquid received in said means for receiving compensates for the entrained moisture in said discharge.

3. A weighing device including a moisture compensating system comprising hopper means for discharging at a substantially constant rate an aggregate material normally having some entrained moisture therein, weighing means for receiving and weighing the discharge of aggregate material, spaced electrode means adapted to be connected to a source of electrical energy by suitable electrical circuitry, said spaced electrode means mounted intermediate said discharge means and said weighing means and mounted in the normal path of discharge from said hopper means, whereby said entrained moisture electrically connects said spaced electrode means so that electrical energy commensurate with the percentage of entrained moisture flows in said circuit, signal generating means connected to said circuitry for generating a signal commensurate with the electrical energy therein, valve means adapted to be connected to a source of liquid, said valve means being connected to said signal generating means for proportional actuation thereby so as to regulate the rate of flow of liquid, and means for receiving said liquid, mounted .on said weighing means, whereby the liquid received in said means for receiving compensates for the entrained moisture in said discharge.

4. A weighing device including a moisture compensating system comprising hopper means for discharging at a substantially constant rate an aggregate material normally having some entrained moisture therein, weighing means for receiving and weighing the discharge of said aggregate material, said weighing device having a pivoted balance arm, spaced electrode means adapted to be connected to a source of electrical energy by suitable electrical circuitry, saidspaced electrode means mounted intermediate said discharge means and said weighing means and mounted in the normal path of discharge from said hopper means, whereby said entrained moisture electrically connects said spaced electrode means so that electrical energy commensurate with the percentage of entrained moisture flows in said circuit, signal generating means connected to said circuitry for generating a signal commensurate with the electrical energy therein, valve means adapted to be connected to a source of liquid, said valve means being connected to said signal generating means for proportional actuation thereby so as to regulate the rate of flow of liquid, and means for receiving said liquid, mounted on said weighing means, whereby the liquid received in said means for receiving compensates for the entrained moisture in said discharge.

5. A weighing device including a moisture compensating system comprising hopper means for discharging at a substantially constant rate an aggregate material normally having some entrained moisture therein, weighing means for receiving and weighing the discharge of aggregate material, said weighing means having a pivoted balance arm, spaced electrode means adapted to be connected to a source of electrical energy by suitable electrical circuitry, said spaced electrode means mounted intermediate said discharge means and said weighing means and mounted in the normal path of discharge from said hopper means, whereby said entrained moisture electrically connects said spaced electrode means so that electrical energy commensurate with the percentage of entrained moisture flows in said circuit, signal generating means connected to said circuitry for generating a signal commensurate with the electrical energy therein, valve means adapted to be connected with a source of liquid, said valve means being connected to said signal generating means for proportion-a1 actuation thereby so as to regulate the rate of flow of liquid, and means mounted on said balance arm for receiving said liquid, whereby the liquid received in said receiving means increases said predetermined amount an amount suflicient to compensate for the weight of the entrained moisture.

6. A device for measuring aggregate material and the liquid to be used in concrete comprising, means for discharging at a substantially constant rate aggregate material normally having some entrained moisture therein, electrode means adapted to be connected to a source of electrical energy by suitable electrical circuitry, said electrode means mounted in the path of said discharge means, whereby said entrained moisture actuates said electrode means so that electrical energy commensurate with the percentage of entrained moisture flows in said circuit, means for receiving and measuring the discharge of aggregate material, a valve means adapted to be connected to a source of liquid, said valve means being connected to said electrical circuitry for proportional actuation thereby so as to regulate the rate of flow of liquid, means for receiving said liquid from said valve means, mounted on said measuring means, whereby the liquid received in said means compensates for the entrained moisture in said discharge, a water measuring device for dispensing a predetermined amount of Water, and means for receiving said liquid, connected to said water measuring device, so that the liquid received in said means for receivng compensates for the entrained moisture in said discharge.

7. A device for measuring aggregate materials and the liquid to be used in concrete comprising, means for dis charging at a substantially constant rate aggregate material normally having some entrained moisture therein, spaced electrode means adapted to be connected to a source of electrical energy by suitable electrical circuitry, said spaced electrode means mounted in the path of said gravity discharge from said discharge means, whereby said entrained moisture electrically connects said spaced electrode means so that electrical energy commensurate with the percentage of entrained moisture flows in said circuit, weighing means for receiving and weighing the discharge of aggregate material in predetermined amounts, said weighing device having a pivoted balance arm, signal generating means connected to said circuitry for generating a signal commensurate with the electrical energy therein, a valve means adapted to be connected to a source of liquid, said valve means being connected to said signal generating means for proportional actuation thereby so as to regulate the rate of flow of liquid, means mounted on said balance arm for receiving said liquid from said valve means, whereby the liquid received in said receiving means increases said predetermined amount an amount suificient to compensate for the weight of the entrained moisture, means for weighing a predetermined amount of water, said water weighing device including a pivoted balance arm, and means mounted on said balance arm of said water weighing device for receiving said liquid, whereby the liquid received in said receiving means decreases said predetermined amount of water by an amount equal to the weight of the entrained moisture.

8. A device for measuring aggregate materials and the liquid to be used in concrete comprising, means for discharging at a substantially constant rate aggregate material normally having some entrained moisture therein, spaced electrode means adapted to be connected to a source of electrical energy by suitable electrical circuitry, said spaced electrode means mounted in the path of said gravity discharge from said discharge means, whereby said entrained moisture electrically connects said spaced electrode means so that electrical energy commensurate with the percentage of entrained moisture flows in said circuit, weighing means for receiving and weighing the discharge of aggregate material in predetermined amounts, said weighing device having a pivoted balance arm, signal generating means connected to said circuitry for gencrating a signal commensurate with the electrical energy therein, a valve means adapted to be connected to a source of liquid, divider means for dividing the liquid {from said valve means into two substantially equal parts, said valve means being connected to said signal generating means for proportional actuation thereby so as to regulate the rate of flow of liquid, means mounted on said balance arm of said aggregate Weighing device for receiving one of said parts of liquid from said divider valve, whereby the liquid received in said means for receiving increases said predetermined amount of aggregate an amount sutficient to compensate for the weight of the entrained moisture, means for weighing a predetermined amount of water, said water weighing device including a pivoted balance arm, and means mounted on said balance arm of said water weighing device for receiving the other of said parts of liquid from said divider valve, whereby the liquid received in said means mounted on said water weighing device decreases said predetermined amount of water an amount substantially equal to the entrained moisture in said aggregate.

9. A device for measuring aggregate materials and the liquid to be used in concrete comprising, means for gravity discharging at a substantially constant rate aggregate material normally having some entrained moisture therein, spaced electrode means adapted to be connected to a source of electrical energy by suitable electrical circuitry, said spaced electrode means mounted in the path of said gravity discharge from said discharge means, whereby said entrained moisture electrically connects said spaced electrode means so that electrical enengy commensurate with the percentage of entrained moisture flows in said circuit, weighing means for receiving and weighing the discharge of aggregate material in predetermined amounts, said weighing device having a pivoted balance arm, signal generating means connected to said circuitry for generating a signal commensurate with the electrical energy therein, a source of substantially constant pressure liquid, divider means for dividing the liquid from said valve means into two substantially equal parts, a valve means for controlling the flow of said liquid, said valve means being connected to said signal generating means for proportional actuation thereby so as to regulate the rate of flow of liquid, means mounted on said balance arm of said aggregate weighing device for receiving one of said parts of liquid from said divider valve, whereby the liquid received in said means for receiving increases said predetermined amount of aggregate an amount sufiicient to compensate for the weight of the entrained moisture, means for Weighing a predetermined amount of water, said water Weighing device including a pivoted balance arm, and means mounted on said balance arm of said water weighing device for receiving the other of said parts of liquid from said divider valve, whereby the liquid received in said means mounted on said Water Weighing device decreases said predetermined amount of water an amount substantially equal to the entrained moisture in said aggregate.

References Cited in the file of this patent UNITED STATES PATENTS 1,640,073 Hapgood Aug. 23, 1927 1,878,179 Rawling Sept. 20, 1932 2,031,146 Dodge Feb. 18, 1946 2,559,308 Martinson July 3, 1951 2,581,950 Glegg Jan. 8, 1952 2,626,121 Sachse Jan. 20, 1953 2,750,144 Beckwith June 12, 1956 2,958,820 Voik Nov. 1, 1960 

1. A WEIGHING DEVICE INCLUDING A MOISTURE COMPENSATING SYSTEM COMPRISING HOPPER MEANS FOR DISCHARGING AT A SUBSTANTIALLY CONSTANT RATE AN AGGREGATE MATERIAL NORMALLY HAVING SOME ENTRAINED MOISTURE THEREIN, MEASURING MEANS FOR RECEIVING AND MEASURING THE DISCHARGE OF AGGREGATE MATERIAL, ELECTRODE MEANS ADAPTED TO BE CONNECTED TO A SOURCE OF ELECTRICAL ENERGY BY SUITABLE ELECTRICAL CIRCUITRY, SAID ELECTRODE MEANS MOUNTED INTERMEDIATE SAID DISCHARGE MEANS AND SAID MEASURING MEANS AND MOUNTED IN THE NORMAL PATH OF DISCHARGE FROM SAID HOPPER MEANS, WHERE- 